The present invention relates to a vehicle-installed telephone apparatus which can be additionally supplied with electric power from an external power supply in the vehicle. The present invention also relates to a telephone apparatus which emits a key-click sound from its receiver.
A vehicle-installed telephone apparatus that is directly connected to the vehicle""s battery, which is used as an external power supply, has been contrived to enable communication even when the vehicle is parked and its ignition switch is turned off, by manual switchover to the external power supply. Furthermore, a vehicle-installed telephone apparatus has been contrived that has a switch for switching between an internal power supply and an external power supply, and switches to the internal power supply when the ignition switch is tuned off (Japanese Patent No. 2,845,810). This patent also discloses a vehicle-installed telephone apparatus that has a first switch for turning an internal power supply on and off and a second switch for turning an external power supply on and off, and automatically turns on the power of the apparatus when a key is operated, even if the ignition switch is off, by controlling these switches and using the internal power supply.
However, the conventional vehicle-installed telephone apparatuses required a switch for turning the external power supply on and off, in addition to a switch for turning the internal power supply on and off. Furthermore, when the ignition switch was off, the conventional vehicle-installed telephone apparatuses could not be powered on unless some operation was performed; a passenger not knowing this would first operate the power key. A further problem was that it was not possible, while parked, to see the time, or information about being within communication range, etc., on the display by just picking up the vehicle-installed telephone apparatus.
A telephone apparatus that emits a key-click sound from its receiver for confirmation of the press of a key has also been contrived (Japanese Unexamined Patent Publication No. 62-272738). However, the volume of the key-click sound is adjusted so that just the right sound level is obtained when the key is operated while being viewed at some distance from the eye (about 40 cm, for example). Therefore, when a key is operated during communication, it sounds very loud since it is close to the ear.
The present invention has been made in light of the above problems, with the object of providing a vehicle-installed telephone apparatus that enables communication to continue, by use of an internal power supply, even if the ignition switch is turned off during communication, interrupting the supply of external power.
Another object of the present invention is to provide a vehicle-installed telephone apparatus that can reduce the drain on its internal power supply by using an external power supply, if power is supplied from the external power supply even when the ignition switch is turned off during communication.
Another object of the present invention is to provide a vehicle-installed telephone apparatus that, with a single switch, can perform both manual power-on/off and control of the supply of power from an internal power supply if the supply from an external power supply is halted when the ignition switch is turned off.
Another object of the present invention is to provide a vehicle-installed telephone apparatus that, when the ignition switch is turned off and the supply from the external power supply is halted, can maintain power by using an internal power supply when the telephone apparatus is simply picked up from its holder, and can therefore display information on its display unit without requiring any key operation.
Another object of the present invention is to provide a telephone apparatus that can avoid having the user hear loud click sounds during communication.
A vehicle-installed telephone apparatus according to a first aspect of the present invention comprises:
an internal power supply (20) for supplying electric power within the apparatus;
a connecting unit (21b) for connecting an external power supply (50) from the vehicle in parallel with said internal power supply (20);
a switch (22) for turning on and shutting off the supply of electric power into the apparatus from said internal power supply and said external power supply, which are connected in parallel;
ignition-on/off detection means (17) for detecting whether the ignition switch of the vehicle is on or off; and
control means (12) for controlling said switch so as to supply electric power to the apparatus if communication is in progress, even when said ignition-on/off detection means (17) detects that the ignition switch is off.
A vehicle-installed telephone apparatus according to a second aspect of the present invention comprises:
an internal power supply (20) for supplying electric power within the apparatus;
a connecting unit (21b) for connecting an external power supply (50) from the vehicle in parallel with said internal power supply (20);
a switch (22) for turning on and shutting off the supply of electric power into the apparatus from said internal power supply and said external power supply, which are connected in parallel;
ignition-on/off detection means (17) for detecting whether the ignition switch of the vehicle is on or off;
placement detection means (18) for detecting whether the apparatus is placed in a predetermined position in the vehicle; and
control means (17) for controlling said switch so as to supply power to the apparatus if said placement detection means (18) detects that the apparatus is not placed in the predetermined position, even when said ignition-on/off detection means (17) detects that the ignition switch is off.
A telephone apparatus according to a third aspect of the present invention comprises:
a speaker (4) which is disposed in the receiver (40) and emits a key-click sound; setting means (12) for setting the volume of the key-click sound emitted from said speaker; and control means (12) for adjusting the key-click sound to at most a predetermined volume during communication, and adjusting the key-click sound to the volume set by said setting means if communication is not in progress.